But many people do not respond to these treatments, or cannot take them because of other health problems, and seek alternative or herbal remedies.

Milk Thistle Fails to Help Hep C

Researchers say milk thistle is commonly used by people with liver disease. In fact, a third of people with chronic hepatitis C say they have used the herbal treatment for their disease.

The flowering herb is related to the daisy and ragweed family. The main ingredient in milk thistle, silymarin, is thought to have anti-inflammatory properties that may benefit people with liver disease.

Until now, studies examining milk thistle's effectiveness in treating a variety of liver diseases have produced mixed results.

In this study, researchers looked at the effects of milk thistle in treating 154 people with chronic hepatitis C who did not respond to interferon-based treatments.

The people were divided into three groups and received either 420 or 700 milligrams of milk thistle or a placebo three times a day for 24 weeks.

The results showed the herbal treatment did not significantly change or improve liver function at either dose, based on measurements of an enzyme that reflects liver function (serum alanine aminotransferase or ALT).

By the end of the study, only two people in each treatment group had a significantly improved level of the liver enzyme.

In addition, researchers did not find any improvements in physical or mental quality of life measures or depression among milk thistle users.

"Silymarin did not provide greater benefit than placebo for patients with treatment-resistant chronic HCV infection," researcher Michael W. Fried, MD, of the University of North Carolina, and colleagues write in the Journal of the American Medical Association.